(1)6x^2-7x+1=0 (2)5x^2-9x-18=0 (3)4x^2-3x=52 (4)5x^2=4-2x

(1)6x^2-7x+1=0 (2)5x^2-9x-18=0 (3)4x^2-3x=52 (4)5x^2=4-2x
(1)6x^2-7x+1=0 (2)5x^2-9x-18=0 (3)4x^2-3x=52 (4)5x^2=4-2x

(1)6x^2-7x+1=0 (2)5x^2-9x-18=0 (3)4x^2-3x=52 (4)5x^2=4-2x
(1)6x^2-7x+1=0
(6X-1)(X-1)=0 则X=1或1/6
(2)5x^2-9x-18=0
（5X+6）*（X-3）=0 则X=-6/5或3
3)4x^2-3x=52 4X^2-3X-52=0
(X-4)(X+13)=0 X=4或-13
5X^2+2X-4=0
5(X+1/5)^2-4-5*(1/5)^2=0
5(X+1/5)^2=21/5
(X+1/5)^2=21/25
X1=根号（21）/25-1/5
X2=-根号（21）/25-1/5

1:(6x-1)(x-1)=0 x1=1/6 x2=1 2:(x5+6)(x-3)=0 x1=-5/6 x2=3

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